Direct gap III-V semiconductor materials have strong absorption properties and have been found to be suitable for high efficiency solar cell applications, particularly portable applications. Small thicknesses of these materials, in the order of a few microns, are sufficient for absorbing a large portion of the solar spectrum. Conventional techniques for making high efficiency III-V solar cells can involve the epitaxial growth of relatively complicated structures using MOCVD (metalorganic chemical vapor deposition) and MBE (molecular beam epitaxy) systems. Despite the high efficiency of epitaxially grown III-V solar cells, the high cost of epitaxy presents challenges to the production of cost-competitive III-V solar cells for terrestrial applications.
GaAs has a relatively wide energy gap (1.4 eV) and in turn offers a high open circuit voltage. Such properties make it suitable for single junction solar cells. GaAs further exhibits high absorption of the solar spectrum that can be converted to a high short circuit current.